An evaluation was made of the contraceptive efficacy of an oral tablet containing 2 mg or norethin-drone and 0.1 mg of 3-methyl-ether of ethinyl estradiol (mestranol), administered in a dosage of 1 tablet daily in repeated courses of 21 days. In 306 women of proven fertility, studied through a total of 1,852 cycles, not a single pregnancy occurred during treatment. Secondary therapeutic benefits were noted in relief of pre-existing menorrhagia and dys-menorrhea in a number of cases. The method was highly acceptable to the vast majority of subjects and devoid of any serious side effect.